The subjunctive past is formed using the subjunctive present of auxiliary verbs avoirconjugaison or êtreconjugaison + the past participle of the verb.

appeler que j’aie appelé that I called (or ‘I had called’)comprendre que tu aies compris that you understood (or ‘you had understood’)avoir que nous ayons eu that we had (or ‘we had had’)partir qu’ils soient partis that they left (or ‘they had left’)